Improvement in the art of increasing the strength ofwrought-iro fl



i duetors of heat,

Unire-n STATES PATENT OFFICE.

WALTER n. JOHNSON, OF PHILADELPHIA, PnNNsLvANIA.

IMPROVEMENT 1N THE ART or tNcREAstNe THE STRENGTH oFwRoucHT-mon-Ano STEEL.

Specification forming part of Letters Patent No. 826, dated July 9, llllizl;

by vdeclare that the following is a full and exact .sleseription'of the machinery forfcarr'ying into e`ect the said improvement.

I coustructta double trough or box of metal or other convenient material capable of sustaining the action of irewhich trough I place' over a flue or hot-air conductor supplied with hot air, gas, or smoke fromf stoves, lire-places, or furnaces situated at a convenient distance below it., Between the two parts ot' the said double trough or box there is included through the'whole length of the samea space or cavity for containing and conducting the hot air, gas, A 'or vapor which I admit into it through holes or valves inthe outer shell or box over Ethe hot-air flue already described. This cavity I call the heating-box. The form of the cross- `section of theheatinghox will depend on that o'f Ythe two troughs which compose it, and will '.beeither rectangular, elliptical, or formed of `two arcs ot circles greater than semicircles,

or in anyfothr form which may be most cou- ,t veillent for. the kind of work to be done. The

"proportions of the length, breadth, and height of. the box must iu like manner depend on the formand thequantity ofthe materials which it may be found necessary to place withiny it at any one time- The two, troughs dcenstitnting thel heating-- box-may beunited by riveting er formed tou lgeth'er by casting. There is an opening on of the inner trough. through its whole `f=length, by which thematerials to be operated if upon 4are introduced; but alcover or covers of iron or other materials mayA be adnptedyto fitA it in such manner as to .prevent the escape of heat from within, Said covers may be formed l either ef simple sheets of metal shaped in the vproper manner, or .they may be menallic bones lled with charcoal., dust, or other ncnccn- Ihe aforesaid. box cr trough is to be set in bricktwork er other substantial fire-prooi? materiale conducting substances, except the top, ends,

the evaporation of any liquid found best adapted to each particular form and surrounded by non a v mayferm a how each way trom tue centralv and such other parts as may be exposed for the purpose of bringing ont thepyrometric rods, hereinafterdescrihed. y

In the bottom" f the outer shell or trough,`

or at the ends in the space between the two, are a number of holes for admitting hot air, gas, vapor, flame,-or smoke into the heatingbox, and from the topof said box, eoither at the ends or at any 'convenient intermediate points, are flues or tubes-for carrying olf the hot air 'or gas after it has traversed the heat- A ing-box. Y

' In order to measure the temperature of the inner trough and of its contents,l,employ any, c

form of thermometer or pyrometer, o r thefter pansion or fusion of any 'solid suhstaucesforand size of apparatus. Bars of metal, either simple or compound, and traversing the 'heat ing-box' either longitudinally, transversely, `or t in spirals, may by their expansion be made to act on a lever or levers, wheel or wheels, and give motion to indexes moving over graduated, straight, or curved lines.

For heating apparatus on a large scale I em:

ploy the" following construction ot' apparatus to serve as a` pyrometer: On the insidesof the inner trough, near the bottom, are two projections lof metal at a convenientd istanceapart, between which are-to be placed the two ends of a bar of brass,sc flohg'astdrequirsl-eogbc I bent or-.curved slightly'u ordcrto be inafo :enter between the said projections, in. one of Awhich isA a screw to `-regulate thec'urvature of "the'bar by increasing crdiniinishing thepres'sureon its twoends.

From'the middle of 'the saidber cai' 'brass there proceeds a rod, `'pessing outthrough the sigle, of double trough hyisiots perforated i'oijthat-purpose, and the sai rodgves motion to levers er wheel-work ib'meving indexes, as before stated;

Instead of connecting the brass bar to the side of the heating-box, I shall sometimes attach it in a manner similar to that above described to a stiff bar or red of cast-iron, plumbage, glass, or other substance of a los.7 rate of expansion hy heat, and shall, when necessary,

use two bars of brass on opposite sides of the same" bar of therother material, so that they which maylhe e ses line or har. In the latter case the instrument will bear a. near resemblance to Regniers py romeier, and the rod will pass from one brass har to tlre other to move the index situated on the latter, traversing in its course theintermediete bar of the material of low expansion.

When the expansion of solids is employed lfor indicating the temperature of the heating apparatus, l make use of the same to close the holes in the outer box already mentioned and to open a register from the flue beneath the heatingfbox in 2 o an escape-pipe connected with i the. same, thei-cby allowing the heated air to Y pass off without coming in contact with the inner trough.

When I mark and regulate the temperature of my heating apparatus by the expansion of barsand the motion of indexes and valves, as already described, I graduate the scales over which said indexes are to pass by ascertaining j the pointsat which they stand at two or more given temperatures in the' following manner:

` After establishing the heating-box and pyrometer rmly'intheir places, I surround the pyrometer with snow or pounded ice, which is allowed to remain until the whole apparatus has acquire/l a temperature of 320 Fahrenheit,

which is marked at the point where the index then stands. Heat is'then applied by lighting tires in the stoves or furnaces, the ice' is melted and made to boil briskly, surrounding the pyrometer with either boiling-water or steam,'2and when thelindex becomes stationary I mark the point 2120. The water is next removed, and around the pyrometer-bars are wrapped leaves, strips, or masses of pure tin, after which the heat is very carfully raised un-l .til the-same shall be perceived' vto be melting and falling oft', the point at .which the index' then stands is marked ,4420.- A number of thin rglass flasks of mercury aire then disposed along contiguous to the pyrometer-bars, and when they begin'to boil .the Scale vis marked 6520 at the point denoted by the index. When I would mark higher temperatures than that of boiling mercury I ascertain them 'by placing on or near the pyrometer-bar an iron vessel to hold melted tiri, into which is plunged the standardpiece of a steam-pyrometerJ NThe apparatus is Athen heated to any required extent, and, noting the position -of the index, I

withdraw the standard-piece and immediately plunge it into the boiling water of the pyrometer vto which it belongs, to ascertain in the -usual manner the number of degrees` which lmenthe set upon the point which was given by the index on taking the standard-piece out of the tin.

Another mode in which I regulate the temperature of the heating-box is by making 'it air-tight; but, instead of using itas a-passage for hot air, .`placing within it a quantity of mercui-y or other liquid havingahigh boiling-point :sufficient to occupy-all that part ofthe lower or outer trough which is exposed to the flue below it. The inner trough and thepieces of metal under process will then be heated by the 'of establishing it in iixedand solid'masonry, Y

Ifplace itron a car, together with its furnace and appendages, and-the said car is thenset on rails beneath 'thepiece'of metal to beact'ed on and caused to move at a convenient speed from one end to the other of the iron', communicating in succession the same temperature to every part ofthe piece. This method is particularly applicable to the wire cables used for sustainingsuspensonfbridges. To know when veach part ofthe metal has arrived at the proper' Y;

temperature, sheets of metal or of sonic alloy which melts ata temperature below 6000Fahr enheit are disposed at, short distances along its whole length, and the velocity ofthe car is regulated by the' readiness with y. which they l are melted off.

Instead ofl the kind of heating'apparatus and machinery herein employed for increasing the strength of iron by the process ot' thermotension, I shall,when iron is manufacturedby rolling, whether into bars or sheets, performthat process by drawing it for the last time forcibly through'. the rolls while the tempera-- ture is notabove 6000 Fahrenheit. In ,like manner, inmanufacturing wire I placeaheatin g apparatus in such a position thatthe wire, after passing the draw-plate, shall be heated to 550o Fahrenheit before it is wound up-fby 'the-spool orreela. Another improvement which Ihave made on the art or process ofin'creasing the strength of riron and steel by the process v`of hot-straining, is, that instead or" the usual forms ofdynamometer or apparatus to measure the yforce applied to @he metal, I make use of a straight beam or lever, one end of which is,

loaded with any convenient constant weight,

and near'the other end is a gudgeon to take hold of two stra-ps, which are placed one on each side of the beam. v,These straps are extended to any convenient distance beyond the beam, and terminate yin `or are connected with the hook orother vholding apparatus for connecting the pieces of iron to the dynamometer.

Between the said gudgeon and the weight, at

the opposite end of thelever, is'placed theful crum which is to be'app'lied ,to thesolid support of the dynaniometer but,A instead ofcxonff sistin g of a simple gudgeoir, 'I formthis vfulcrurn of a solid casting or other stron grpiece of metal bent twice at righ-tanglesandhaving the lever i l traversing its middlgpection .between the two projecting theihentportiou, each vofi lwhichfbeing their reducodfto a proper bearing;

on its principal fnlcrnm, be

ses :a

edge, they constitute together the principal fulcrnm. Tbe'epening between 'the two parts nf this fnlcrnm is inbended to give room for the straps zilreaclj'frlescribed and to allow the fnlcrnmdistnnce to. be im'nishedeg pleasure. The weighted end-'ofthe beam plays between twoqnedranlal arcs of :i circle, each of which is cnt into c ratchet and llas cnjzie'sie cf the number of tons or other Weghtsgwhich the dyuamometermeasntes, en 'lie principle 'that the force applied on the shorter erm of tbebeaxn in a, horizontaldiection will, if thebm be supposed to be, when unl0aded iself.blanced Srectly proper-4 tioni tc the weigbtplacedionf-the longer arm .multiplied by thelength of 'that armanda'gain mlxltiplied 'by the sinevof `theangle xnea'snrecl onitlxe arc, reckoning from the lowest; pointgcf s a iebnd inversely propqgticnal to tbeflength cff l.

ille shorter arm multiplied by the cosinepf the samenngle measured in the xnannerjuststted,

The above-described heating-box is, when used, to lie-placed sc time c mechanical power forstrnining the' metal may beat or opposite to one end of the saidv box mul the yrmx'xbmel ter above described. at the other end, with prcperhcldin'g machinery to cnnecbeaeh with tlbepieces ci' the metal which are to undergo thermo-tension.

What I claim as new in thisvinvention isi--` 1. The above-described 1l0ubl3'trough,forn1 Y ing a ln'antingfncm with its apertures, valves, registers, nes, receptacles for condensed vnpor, and ses other appendages, as the same are 'applicable to the purpose ofincreasng the strength of iron and steel in the process of .straining the saline al: a high temperature.

2\Tbe' increasing of the strength of bars, v

rods, or yplates el iron byV drawing themwh'le L l hot through the rolls by mechanical power of any suitable kin.'

3. The incregs'ingcf thestrength of 'wireby healing tbesnnie'after'passin'g through .the

drnw-plate,z as described above.

WALTEBR; JOHNSON.

VWitnesses:

1J, BQUVRER,

Tues.. FLETCHER. 

